Process of making translucent opal glass.



ing is a specification.

' No. 'rzaasa v UNiTED STATE-s" d see"; AVAILABLE cos Patented December20, 19st.

J SEPH EMrnna OFVBERLIN, GERMANY;

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Be it known that I, J osnPHKEMPNEa, a sub eet of the Em perorof'Germany,residing at 20 Flensburgerstrasse, BerlimGer-many, have invented a newand useful Process of Making Translucent Opal Glass, of which the followIn my process I make the opal glass of sand,

soda, feldspar poor of lime, and sodium silicofluorid. v

In the process known till now the opal glass was made by addingalkalinesilicofluorid to the usual glass-flit, (alkaline lime silicate;)but this addition causes difliculties, having a detrimental influence onthe opalescence and the fusibility of the glass-frit. If no lime isadded, then a suitable quantity of alumina must he introduced into theglass-frit, as is already well known in the manufacture of opalglassthrough the use of cryol-ite (an element containing fluorin.)

For the purpose ofmaking in an economical way an opal-glass fritaccording to my inven- .tion the same is composed of sand, soda,feldspar poor of lime, and sodium silicofluorid, the two latterconstituents in the proportion of two to one; but the feldspar of themixturemay amount to three-fourths and the sodium silicofluorid may sinkto one-fourth. 'A s'uitcofluorid, on'hundred and siiityto one hundredand eighty parts of silicic acid, and thirty-seven times in tliepve'n. Ij The glass-frit mixture is suitable for a f eh l spar of thefollowing'compositionz "-silieic act 2.

i 68.15 per-cent y-alumina; 18.58fper' eon potash, 8.90 per. cent;soda,- 3.45 per cvmlime, 077 per-cent; magnesia, 0.11 per cent water,0.04 per cent The u's e of alumina in combination with [sodium sheofluorid in manufacturing opal glass is already known:

butsuch a. glassfrit hvas'never entirely true of lime. 1 r a,

Having now described the nature of my invention, what I claim is. v

*1; In a processof making opal glass the use of agla'ss-frit composed-ofsand, soda, feldspa 1- poor of lime, and s'odium silieofluoridtho-latterin the proportions-0f two to one, as and for of a glass-fritcomed of one hundred parts of .feldspar andso ium silicofluorid, onehundred and sixty to one hundred and eighty partsof silieic acid andthirty-sevenand one-halt to fifty parts ofsoda,as-'and for the purposespecified." p r JOSEPH KEMBNER. lWitnesses:

HENRY HAsrnR, WILLIAM Mama.

2. In a process of making opal glass the use

